Diagonal-stride-simulating roller ski

ABSTRACT

An apparatus supporting “dry land” simulation of the diagonal stride cross-country skiing technique. The apparatus may include a roller ski comprising at least two wheel configured to roll on a surface and a stop connected to the roller ski. The stop may selectively engaging at least one of the surface and the at least two wheels in response to a force of at least a threshold magnitude urging the roller ski toward the surface to resist rearward roll of the roller ski on the surface. The resistance to rearward roll may vary with the force.

BACKGROUND

1. The Field of the Invention

This invention relates to dry land training for cross-country skiing and, more particularly, to novel systems and methods for roller skis simulating the diagonal stride.

2. The Background Art

In competitive cross-country skiing, the race is typically won or lost on the hills. While a competitor may gain a few seconds on the flatter, faster portions of a course, the hills provide the greatest test of a competitor's strength, cardiovascular efficiency, technical efficiency, and mental courage. In the classic technique, the diagonal stride is the hill-climbing technique most often used. As a result, more time is won or lost while employing the diagonal stride than perhaps any other classic technique. Accordingly, the diagonal stride is arguably the most important technique in any cross-country race in the classic technique.

As may be appreciated, in most part of the world, snow is a seasonal occurrence. However, training for competitive cross-country skiing is not. To achieve and maintain sufficient strength, cardiovascular efficiency, technical efficiency, etc. to compete an any significant level, skiers must typically train during seasons lacking in snow.

Roller skis have been developed as a tool for “dry land” training. Roller skis provide a simulated skiing experience that may be performed on roads, trails, and the like. Roller skis have become a necessary part of training. Due to travel costs and climatic fluctuations, it is unlikely that any skier could compete at an elite level without significant training on roller skis.

However, despite this reliance on roller skis, no current roller skis provide adequate simulation of the diagonal stride. Current “classic” roller skis typically provide unidirectional travel regardless of the weight applied to the roller ski. Accordingly, skiers using such roller skis may be imprecise in their technique, yet still obtain sufficient “kick.” For this reason few athletes use roller skis to train in the diagonal stride, as they wish to avoid acquiring bad habits. Rather, they typically only use the classic roller skis to practice double poling or double poling with a kick.

What is needed is a roller ski providing a realistic simulation of all aspects of the classic technique.

BRIEF SUMMARY OF THE INVENTION

In view of the foregoing, in accordance with the invention as embodied and broadly described herein, a method and apparatus are disclosed in one embodiment of the present invention as including a roller ski supporting roll across a supporting surface. To simulate the diagonal stride, a stop may be connected to the roller ski. The stop may resists rearward roll of the roller ski on the surface in response to a force of at least a threshold magnitude urging the roller ski toward the surface.

In selected embodiments, the strength (magnitude) of a stop's resistance to rearward roll may depend on the downward force generated and applied by the skier to the roller ski. That is, the resistance to rearward roll that is generated may vary (e.g., proportionally vary) with the magnitude of the downward force. For example, once a threshold downward force is achieved, any additional downward force will continue to increase the resistance to rearward roll provided by the stop.

Because a skier is responsible for generating and applying the force of a threshold magnitude (i.e., at least a threshold magnitude) to the roller ski 44, that force is not susceptible to generic, across-the-board characterization. The magnitude may vary between different skiers and their corresponding weights and skiing styles. In general, however, a threshold magnitude will be greater than the entire weight of the skier.

A stop may have any suitable structural configuration to support the desired simulation. In selected embodiments, a stop may resists rearward roll by engaging the supporting surface upon which the roller ski travels. For example, the deck or intermediate member of a roller ski may be cambered. This camber may cause the intermediate member to act as a leaf spring, lifting the stop away from the surface when less than a force of a threshold magnitude is applied to the roller ski.

Alternatively, a stop may resist rearward roll of a roller ski by resisting rotation of at least one of the first and second wheels. That is, a stop (or multiple stops) may engage a first wheel, second wheel, both the first and second wheels, or the like. For example, in one embodiment, an intermediate member may include one or more flex regions. A flex region may permit a wheel mount to move (e.g., translate, rotate, or some combination thereof) with respect to the remaining portion of the intermediate member. A stop may rigidly extend from the remaining portion to a location over one of the wheels. Accordingly, a force of a threshold magnitude may flex the flex region sufficiently that the wheel contacts the stop. This contact may result in a frictional engagement resisting further rotation of the wheel.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features of the present invention will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are, therefore, not to be considered limiting of its scope, the invention will be described with additional specificity and detail through use of the accompanying drawings in which:

FIG. 1 is side view of a skier performing the diagonal stride;

FIG. 2 is side view of a classic cross-country ski in a neutral or unloaded position;

FIG. 3 is a side view of the classic cross-country ski of FIG. 2 with the ski partially loaded;

FIG. 4 is a side view of the classic cross-country ski of FIG. 2 with the ski fully loaded;

FIG. 5 is a perspective view of a roller ski having a wheel-type stop for simulating the diagonal stride in accordance with the present invention;

FIG. 6 is a side view of the roller ski of FIG. 5 with the ski in an unloaded position;

FIG. 7 is a side view of the roller ski of FIG. 5 with the ski in a fully loaded position;

FIG. 8 is a perspective view of a roller ski having flex region and stop for simulating the diagonal stride in accordance with the present invention;

FIG. 9 is a side view of the roller ski of FIG. 8 with the ski in an unloaded position;

FIG. 10 is a side view of the roller ski of FIG. 8 with the ski in a fully loaded position;

FIG. 11 is a cut-away perspective view of the flex region of the ski of FIG. 8;

FIG. 12 is a partial side view of a roller ski having an alternative embodiment of a flex region and stop for simulating the diagonal stride in accordance with the present invention;

FIG. 13 is a cross-sectional side view of the roller ski of FIG. 12 with the ski in an unloaded position;

FIG. 14 is a cross-sectional side view of the roller ski of FIG. 12 with the ski in a fully loaded position;

FIG. 15 is a perspective view of a roller ski having a stop comprising a pivoting brake pad for simulating the diagonal stride in accordance with the present invention;

FIG. 16 is a side view of the roller ski of FIG. 15 with the ski in an unloaded position;

FIG. 17 is a side view of the roller ski of FIG. 15 with the ski in a fully loaded position;

FIG. 18 is a partial perspective view of roller ski equipped with one embodiment of a block-type stop for engaging a supporting surface in accordance with the present invention; and

FIG. 19 is a partial perspective view of a roller ski equipped with one embodiment of a break-away-type stop for engaging a supporting surface in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It will be readily understood that the components of the present invention, as generally described and illustrated in the drawings herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the system and method of the present invention, as represented in the drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of various embodiments of the invention. The illustrated embodiments of the invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout.

Referring to FIG. 1, in cross-country skiing, there are various techniques used by a skier to propel himself or herself across the snow. These techniques may largely be divided into two groups, namely classic and skating. As the name suggests, the classic technique is the older of the two and has been employed for centuries.

The classic technique may include various sub-techniques such as the diagonal stride 10 and the double pole. These sub-techniques are suited to different terrain or snow conditions. For example, double poling may be considered a “high gear.” It utilizes primarily the upper body and includes a significant recovery stroke where no forward motion is being generated. Accordingly, double poling is well suited for fast snow conditions and terrain lacking any significant incline.

The diagonal stride 10 may be considered a “low gear.” It utilizes both the upper body 12 and the lower body 14. The lower body 14 provides an alternating “kick,” while the upper body 12 provides an alternating poling motion. In the diagonal stride 10, the arm 16 and leg 18 corresponding to a particular side of the body are generally moving in opposite directions. For example, when the right leg 18 has completed its kick and is beginning to move forward into its recovery stroke, the right arm 16 is just beginning to move backward into its power stroke. Accordingly, there is typically little “down time” when no forward motion is being generated. As a result, the diagonal stride 10 is well suited for slower snow conditions and terrain with an incline.

Referring to FIG. 2, a ski 20 designed for the classic technique may be divided into three sections, namely, the tip 22, the tail 24, and the kick zone 26. The kick zone 26 is typically positioned between the tip and tail 22, 24. For example, the kick zone 26 may be positioned on the ski 20 in the area corresponding to the binding 28, which provides securement between the skier's boot and the ski 20.

The underside 30 of the ski 20 (the base 30) associated with each section 22, 24, 26 may be configured for its particular function. For example, the camber of the ski 20 ensures that the tip and tail 22, 24 are first to contact the snow 32. Accordingly, the base 30 of the tip and tail 22, 24 may be configured (e.g., waxed) for glide. The kick zone 26, on the other hand, may be configured for grip. For example, the base 30 through the kick zone 26 may be roughed or waxed to engage and grip the snow 32.

Referring to FIG. 3, during double poling or the downhill tuck, the weight of the skier is typically evenly divided between the two skis 20. So divided, the downward force 34 applied to each ski 20 is insufficient to flatten the camber thereof. Accordingly, a gap 36 remains between the base 30 corresponding to the kick zone 26 and the snow 32. So loaded, the ski 20 may continue to efficiently glide over the snow 32.

Referring to FIG. 4, in the diagonal stride 10, the skier initiates the kick phase by stopping the forward glide of one ski 20 (the forward ski 20) over the snow 32. This permits the skier to apply all of his or her weight to that ski 20. Additionally, the skier begins to push himself or herself up away from the snow 32. Thus, according to principles of inertia, that ski 20 is urged down against the snow 32 with a downward force 38 typically greater than the entire weight of the skier.

If the ski 20 is properly fitted to the skier, this downward force 38 should be sufficient to flatten the ski 20. Accordingly, the base 30 corresponding to the kick zone 26 may be pressed firming into contact with the snow 32 causing a frictional engagement therebetween. The skier may then propel himself or herself forward with respect to the ski 20.

The equal and opposite force 40 created by this forward propulsion may be opposed by a frictional force 42 acting between the base 30 of the ski 20 and the snow 32. The greater the downward force 38 generated by the skier, the greater the propulsion-providing frictional force 42. That is, the frictional force 42 is equal to the coefficient of friction (typically a constant for a given base preparation and snow condition) times the downward force 38. Thus, a powerful “kick” requires an effective weighting of the ski 20.

If the ski is altered to lessen the need for proper weighting thereof, the glide (speed) of that ski 20 will likely be compromised. For example, if the camber (spring constant) of the ski 20 is lessened, the base 30 may more easily be compacted against the snow 32. Accordingly, a strong kick may be produced with less effort. However, that also results in more of the kick zone 26 frictionally engaging the snow 32 when it is not wanted or needed (i.e., during double poling or downhill maneuvers). A similar result occurs when the kick zone 26 is lengthened. Thus, a fine balance between the camber of a ski 20, the length of the kick zone 26, and the weighting abilities of the skier is necessary to provide a fast ski 20 that also climbs well in the diagonal stride.

Referring to FIGS. 5-7, in selected embodiments in accordance with the present invention, a roller ski 44 may define coordinate axes comprising longitudinal 45 a, lateral 45 b, and transverse 45 c directions substantially orthogonal to one another. A roller ski 44 may include a first wheel 46 positioned proximate a first end 48 thereof. A second wheel 50 may be positioned proximate a second end 52 of the roller ski 44. An intermediate member 54 may extend to connect the first wheel 46 to the second wheel 50.

If desired or necessary, more than one wheel may be positioned at each end 48, 52 of the roller ski 44. For example, “a first wheel 46” may be one of a pair of first wheels 46 positioned proximate the first end 48 of the roller ski 44 and spaced in the lateral direction 45 from one another. Similarly, “a second wheel 50” may be one of a pair of second wheels 50 positioned proximate the second end 52 of the roller ski 44 and spaced in the lateral direction 45 from one another.

In general, the first and second wheels 46, 50 may configured and positioned to rotate about axes extending in the lateral direction 45 b. The axis corresponding to the first wheel 46 may be spaced from the axis corresponding the second wheel 50. Accordingly, in selected embodiments, the intermediate member 54 may extend substantially longitudinally 45 a to connect the first wheel 46 to the second wheel 50.

In certain embodiments, an intermediate member 54 may include a first wheel mount 56 extending to engage the first wheel 46. A second wheel mount 58 may extend to engage the second wheel 50. A deck 60 may extend to connect the first and second wheels mounts 56, 58. The deck 60 may provide a location for securing a binding 28 to the roller ski 44.

Wheels 46, 50 in accordance with the present invention may be formed in any suitable shape. In general, the wheels 46, 50 may have a shape (e.g., width) selected to impart adequate stability to the roller ski 44. Wheels 46, 50 may be formed of any suitable material or combination of materials. For example, in certain embodiments, a wheel 46, 50 may comprise a rubber exterior formed around a metallic or polymeric hub. The hub may then support any appropriate bearing or axle 64.

In selected embodiments, the rubber used to form the wheel 46, 50 may provide a desired rolling resistence. For example, a softer rubber may increase the rolling resistance of the wheel 46, 50. Accordingly, the hardness of the rubber may be selected to provide a realistic snow-like resistance. Additionally, or in the alternative, the hardness of the rubber may be selected to provide a speed limiter reducing the speed achieved on downhill sections.

Wheel mounts 56, 58 in accordance with the present invention may be of any suitable type. For example, in selected embodiments, wheel mounts 56, 58 may comprise individual flanges 62 extending from the deck 60 to engage an axle 64 of the corresponding wheel 46, 50. Alternatively, the wheel mounts 56, 58 may each comprise a monolithic fork formed as a single piece to extend and bracket the corresponding wheel 46, 50.

Wheel mounts 56, 58 in accordance with the present invention may be formed of any suitable material or combinations of materials. Characteristics that may be considered in selecting suitable materials may include cost, availability, strength, density, elasticity, shock resistance, toughness, durability, corrosion resistance, and the like. In selected embodiments, suitable materials may include metals, metal alloys, polymers, reinforced polymers, and composites.

A deck 60 may be formed of any suitable material or combination of materials. Characteristics that may be considered in selecting suitable materials may include cost, availability, strength, density, flexibility, fatigue life, shock resistance, toughness, durability, corrosion resistance, water resistance, and the like. In selected embodiments, suitable materials may include metals, metal alloys, polymers, reinforced polymers, composites, woods, and the like. For example, in one embodiment, a deck 62 may be formed of a wood laminate. In other embodiments, a deck 62 may be formed to include a light weight core (e.g., a honeycomb core). In still other embodiments, deck 60 may be formed of a tubular metal material.

In selected embodiments, the wheel mounts 56, 58 may be formed of one or more materials dissimilar from those of the deck 60. For example, one or more of the wheel mounts 56, 58 may be formed of metal, while the deck 60 may be formed of a wood laminate. Alternatively, one or more of the wheel mounts 56, 58 may be formed of a material similar to that of the deck 60. For example, the wheel mounts 56, 58 and the deck 60 may both be formed of metal. In still other embodiments, one or more of the wheel mounts 56, 58 may be form as a monolithic (seamless) extension of the deck 60.

In operation, a roller ski 44 in may roll on a supporting surface 66 (e.g., road surface 66, trail surface 66). To simulate the diagonal stride 10, a stop 68 may be connected to the roller ski 44. The stop 68 may resists rearward roll of the roller ski 44 on the surface 66 in response to a force 38 of a threshold magnitude urging the roller ski 44 toward the surface 66 (i.e., a force of sufficiently magnitude and acting in the transverse direction 45 c).

A force 38 of a threshold magnitude is generated and applied to the roller ski 44 by the user (skier). Accordingly, it is not susceptible to generic, across-the-board characterization. The magnitude may vary between different skiers and their corresponding weights and skiing styles. In generally, however, a threshold magnitude will be greater than one half of the weight of the skier. Also, in general, the threshold magnitude will be greater than the entire weight of the skier. However, different skiing styles may demand variations or departures from these general rules.

A stop 68 may have any suitable structural configuration to support the desired simulation. In selected embodiments, a stop 68 may resists rearward roll by engaging the supporting surface 66. For example, an intermediate member 54 may be cambered. This camber may cause the intermediate member 54 to act as a leaf spring, lifting the stop 68 away from the surface 66 when less than a force 38 of a threshold magnitude is applied to the roller ski 44.

As the force 38 increases, the camber of the intermediate member 54 may flatten, forcing the stop 68 closer to the surface 66. When a force 38 of a threshold magnitude is achieved, the stop 68 may contact and engage the surface 66. This engagement may resist rearward roll of the roller ski 44 on the surface 44. Accordingly, only after a full, proper weighting of the roller ski 44 may the skier generate a kick.

Furthermore, the strength of that kick (i.e., the strength of the frictional engagement between the stop 68 and the surface 66) will necessarily be depend on the downward force 38 generated and applied by the skier to the roller ski 44. That is, the resistance to rearward roll that is generated varies (e.g., proportionally varies) depending on the magnitude of the downward force 38. Using an electrical analogy, the resistance to rearward roll is analog, not digital.

The camber or spring constant of the intermediate member 54 may match the weight and skiing style of the user. Accordingly, a user may select an intermediate member 54 that will sufficiently flatten with the same downward force that such a user would generate using actual skis on snow. Thus, an intermediate member 54 suitable for one skier may be unsuitable for another. However, once matched, a roller ski 44 in accordance with the present invention may provide a close simulation to the kick achieved by that skier on snow.

For example, the present invention may include a method for matching roller skis 44 to a skier. The spring constant of a skier's actually classic snow skis may be tested. Particular attention may be paid to the downward force necessary to sufficiently urge the kick zone against an underlying surface. Then, an intermediate member 54 matching that spring constant may be selected or manufactured. That is, an intermediate member 54 may be provided that permits contact between the stop and the supporting surface 66 at the same force 38 (or nearly the same force 38) necessary to adequately flatten the kick zone of the snow ski.

Adjustments to an intermediate member 54 may be made to better match the desired spring constant. For example, the cross-section of the intermediate member 54 may be adjusted to fine tune the mechanical characteristics of thereof. Alternatively, or in addition thereto, the positioning of the stop 66 with respect to the roller ski 44 may be varied. Thus, the stop 66 may be positioned to contact the supporting surface 66 just as the resistence of the intermediate member 54 to further deflection reaches the desired level (force).

In selected embodiments, a stop 68 may have any suitable configuration. For example, in one embodiment, a stop 68 for contacting the supporting surface 66 may comprise a piece (e.g., block) of rubber secured to the underside of the intermediate member 54. In another embodiment, a stop 68 may comprise wheel 70 providing unidirectional rotation.

For example, the wheel 70 may rotate about unidirectional bearings, ratchet, or the like. The wheel 70 may be secured to roller ski 44 so that it resists rotation in the direction corresponding to rearward roll of the roller ski 44. However, in certain embodiments, the wheel 70 may be free to rotate in the direction corresponding to forward roll of the roller ski 44. Accordingly, should the wheel 70 inadvertently contact the surface 66 due to some irregularity therein, the wheel 70 will not undesirably stop the roller ski 44.

A stop 68 in accordance with the present invention may be positioned on a roller ski 44 in any suitable location. Suitable locations may include to the front of the binding 28, under the binding 38, to the rear of the binding, or the like. Similarly, the connection of the stop 68 to the roller ski 44 may be accomplished in any suitable manner. For example, in embodiments where the stop 68 comprises a wheel 70, an axle 72 may connect the wheel 70 to the roller ski 44.

An intermediate member 54 may be tailored to accommodate the stop 68. For example, in embodiments where the stop 68 comprises a wheel 70, an aperture 74 may be formed in the intermediate member 54 to accept the wheel 70. In certain embodiments, the thickness 76 of the intermediate member 54 in the transverse direction 54 c may be increase to compensate for the structural weakness imposed by the aperture 74. In other embodiments, the width 78 of the intermediate member 54 in the lateral direction 54 b may be increase to compensate for the structural weakness imposed by the aperture 74.

In still other embodiments, a stop 68 may comprise more than one wheel 70. For example, a wheel 70 a, 70 b may be positioned on each side of the intermediate member 54. In selected embodiments, the size of the wheel 70 may be decreased so that it may fit underneath the intermediate member 54 without the need for an aperture 74. For example, the size of the wheel 70 may be decreased such that a concavity in the underside of the intermediate member is all that is needed to accommodate the wheel 70.

In still other embodiments, a discontinuity 80 in the intermediate member 54 may accommodate the wheel 70. For example, a discontinuity 80 may permit the inclusions of stronger materials 82 (e.g., metals) to bridge the portion of the intermediate member 54 weakened by inclusion of the wheel 70.

Referring to FIG. 8-10, in selected embodiments, a stop 68 may resist rearward roll of a roller ski 44 by resisting rotation of at least one of the first and second wheels 46, 50. That is a stop 68 (or multiple stops 68) may engage a first wheel 46, second wheel 50, both the first and second wheels 46, 50, or the like.

For example, in one embodiment, an intermediate member 54 may include one or more flex regions 84. A flex region 84 may permit a wheel mount 58 to move (e.g., translate, rotate, or some combination thereof) with respect to the remaining portion 86 of the intermediate member 54. A stop 68 may rigidly extend from the remaining portion 86 to a location over one of the wheels 50. Accordingly, a force 38 of a threshold magnitude may flex the flex region 84 sufficiently that the wheel 50 contacts the stop 68. This contact may result in a frictional engagement resisting further rotation of the wheel 50.

Again, the strength of the kick (i.e., the strength of the frictional engagement between the stop 68 and the wheel 50) will necessarily depend on the downward force 38 generated and applied by the skier to the roller ski 44. That is, the resistance to rearward roll that is generated varies (e.g., proportionally varies) depending on the magnitude of the downward force 38. Once the force 38 decreases sufficiently, the flex region 84 may resiliently return to a more neutral position, and the wheel 50 may again rotate freely.

Any suitable structures may be used to create a flex region 84. For example, in certain embodiments, biasing members 88 (e.g., pieces of spring steel 88) may connect a wheel mount 58 to the remaining portion 86 of the roller ski 44. In a neutral, unloaded position, the biasing member 88 may secure the wheel mount 58 in alignment with the remaining portion 86. However, when the roller ski 44 is urged against the supporting surface 66, the biasing members 88 may permit a parallelogram-type deflection of the wheel mount 58 toward the stop 68.

Referring to FIG. 11, the spring constant of the flex region 84 may be selected to permit contact between the stop 66 and the wheel just as the resistence of further flexing of the flex region 84 reaches the desired force. In selected embodiments, the spring constant of the flex region 84 may be controlled by the thickness of the biasing members 88. For example, in one embodiment, if a greater spring constant is needed, thicker pieces of spring steel 88 may be used.

Alternatively, in selected embodiments, additional degrees of control over the spring constant may be desirable. For example, an extension 90 may extend from the remaining portion 86 to engage the wheel mount 58. A resilient member or members 92 may provide the interface between extension 90 and wheel mount 58. Such a resilient member 92 may be comprise a metallic spring, elastomer, or the like. Accordingly, the spring constant of the flex region 83 may be determined by the biasing members 88, the extension 90, and the resilient member 92. Thus, by adjusting the spring constant of any of the various components 88, 90, 92, the overall spring constant of the flex region 84 may be tuned to a particular skier.

Referring to FIGS. 12-14, in selected embodiments, a flex region 84 may comprise a wheel mount 58 connected by a pivot 94 to the remaining portion 86 of the intermediate member 54. A stop 68 may rigidly extend from the remaining portion 86 to a location over the wheel 50. A biasing member 96 may urge rotation 98 of the wheel mount 58 with respect to the remaining portion 86 such that the wheel 50 is urged away from the stop 68. This rotation 98 may be limited in any suitable manner. For example, an abutment 100 between the wheel mount 58 and the remaining portion 86 may limit the rotation 98 of the wheel 50 away from the stop 68.

In such embodiments, a force urging the roller ski 44 downward against a supporting surface 66 may induce a rotation 102 of the wheel mount 58 with respect to the remaining portion 86 such that the wheel 50 is urged toward the stop 68. A force 38 of a threshold magnitude may deflect the biasing member 96 sufficiently for the wheel 50 to contact the stop 68. This contact may result in a frictional engagement resisting further rotation of the wheel 50. This frictional engagement may vary with the magnitude of the downward force 38. Again, once the force 38 decreases sufficiently, the flex region 84 may resiliently return to a more neutral position, and the wheel 50 may again rotate freely.

In selected embodiments, the biasing member 96 of a flex region 84 may be sized, adjusted, or sized and adjusted to provided the desired flexure. For example, in selected embodiments, the biasing member 96 (e.g., a coil spring 96) may be selected accordingly to the expected loads to be applied thereto by the intended user. Additionally, the biasing member 96 may be preloaded. That is, the biasing member 96 may be held in a somewhat compressed state before a user ever applies any weight thereto. By preloading the biasing member 96, a certain amount of weight (downward force 34) may be applied to the roller ski 44 before any deflection of the biasing member 96 is achieved.

In certain embodiments, interfaces 103 may provide the connection between the biasing member 96 and the surrounding components 58, 86. In selected embodiments, the interfaces 103 may register the biasing member 96 with respect to the surrounding components 58, 86 through the use of apertures and corresponding posts sized to register therewithin. Also, by appropriately selecting the size of the interfaces 103, the amount of preload on the biasing member 96 may be controlled. For example, by selecting and installing thicker interfaces 103, the amount of preload may be increased.

Accordingly, through suitable combinations of biasing member 96 selection and preloading, the pivoting of the flex region 84 may be matched to an intended user. Thus, the flex region 84 may permit contact between the stop 68 and the wheel 50 at the same force 38 (or nearly the same force 38) necessary for the intended user to adequately flatten the kick zone of an appropriately fitted snow ski.

Referring to FIG. 15-17, as a cambered intermediate member 54 transitions from a chambered shape to a flattened shaped, the distance between the ends thereof increases. In selected embodiments, this change in dimension may be used as the actuation mechanism for a stop 68. For example, a stop 68 may comprise a brake pad 104 connected to a wheel mount 58 by a pivot 106. A tension member 108 (e.g., one or more wires, cables, steal bands, or the like) may extend from one end 48 of the roller ski 44 to engage the brake pad 104. When the roller ski 44 is in a neutral, chambered position, the brake pad 104 may be spaced from the wheel 50.

As the chamber is flattened by a downward force 38, the ends 48, 52 of the roller ski 44 may be pushed apart. In that the tension member 108 is substantially inextensible, a rotation 110 may be induced in the brake pad 104. The mechanical advantage of the pivoting brake pad 104 may be selected such that a downward force 38 of some threshold magnitude may sufficiently flatten the intermediate member 54 such that the rotation 110 induced causes the brake pad 104 to contact the wheel 50 and resist further rotation thereof.

In selected embodiments, a stop 68 may include a tuner 112 to provide fine adjustments to the positioning of the brake pad 104. For example, in selected embodiments, a tuner 112 may provide the interface between the tension member 108 and one end 48 of the roller ski 44.

In one embodiment, a tuner 112 may include a bracket 114 connected to a wheel mount 56 by a pivot 116. An adjuster 118 may engage one end of the bracket 114. The tension member 108 may engage the other end of the bracket 114. Accordingly, manipulation of the adjuster 118 may cause the bracket 114 to rotate about the pivot 116. This rotation may then adjust the position of the tension member 108 and, consequently, the position of the brake pad 104. Thus, the tuner 112 may position the brake pad 104 so that it engages the wheel 50 at a desired deflection (e.g., flattening) of the intermediate member 54, with the desired downward force 38 associated therewith.

Referring to FIG. 18, in selected embodiments, a stop 68 configured to engage a supporting surface 66 may be structured to minimize the negative effects of road debris and irregularities (pebbles, cracks, etc). That is, should a stop 68 inadvertently engage an irregularity of the supporting surface 66, the roller ski 44 may have a tendency to stop, pitching the skier forward. This stopping effect, if sufficiently abrupt and strong, may cause the skier loose control and crash, resulting in injury.

Accordingly, as presented hereinabove, a stop 68 may comprise wheel 70 providing unidirectional rotation. Should such a wheel 70 inadvertently contact the surface 66 while traveling forward, the wheel 70 may simply roll over the irregularity without undesirably stop the roller ski 44. Alternatively, a less mobile stop 68 may also be configured to minimize the chance and extent of such undesirable stopping.

For example, in one embodiment, a stop 68 may include a block 120 of elastomeric material. The block 120 may have a channel 122 formed therethrough in the longitudinal direction 45 a. The channel 122 may minimize the lateral 45 b profile of the block 120 to decrease the probability of the block 120 inadvertently contacting an irregularity in the supporting surface 66.

In selected embodiments, the leading edge 124 of a block 120 may be tapered to provide a snow plow effect should the bock 120 encounter any movable irregularities (e.g., pebbles). Additionally, or in the alternative, a block 120 may be formed with slots 126 increasing the flexibility of the block 120. Accordingly, the slots 126 may reduce the abruptness and strength of any contact with an irregularity in the supporting surface 66.

In selected embodiments, the interface between a stop 68 and an intermediate member 54 may provide some adjustability. For example, should wear change the dimensions of a stop 68, a skier may be unable to obtain the desired kick. Accordingly, a spacer 128 may control the transverse 45 c position of the stop 68. If desired, a stop 68 may be secured to an intermediate member by one or more fasteners 129 (e.g., removable fasteners such as screws, bolts, or the like). Accordingly, when a different kick is desired, a skier may remove the stop 68, insert a spacer 128 providing a desired change in transverse 45 c position for the stop 68, and re-secure the stop 68.

Referring to FIG. 19, in certain embodiments, a stop 68 may break-away, release, or disengage should it undesirably encounter an irregularity in the supporting surface 66. For example, in selected embodiments, a stop 68 may include a base 130 and a foot 132. The foot 132 may be pivotably connected to the base 130. The base 130, in turn, may be secured to the intermediate member 54 (e.g., the top surface of the intermediate member 54).

A base 130 may include a block 134 blocking rotation or pivoting of the foot 132 past a selected point. Accordingly, when a roller ski 44 in accordance with the present invention is weighted sufficiently, the foot 132 may contact the supporting surface 66. The skier may then move forward and by applying a rearward force 40 to the roller ski 44. Because of the frictional engagement between the foot 132 and the supporting surface 66, the rearward force 40 on the roller ski 44 may urge 136 the foot 132 against the block 134, thereby resisting rearward motion of the roller ski 44. A biasing member 138 may urge 136 the foot 132 against the block 134, thereby removing any slack from the system.

So embodied, a foot 132 may be free to rotate rearwardly 140, opposed in such a direction only by the biasing member 138. Accordingly, should the foot 132 undesirably encounter an irregularity in the supporting surface 66, the foot 132 may pivot rearwardly 140 without undesirably stopping or slowing the roller ski 44.

In selected embodiments, a stop 68 may include more than one foot 132. For example, in one embodiment, a pivot 142 may extend laterally through a base 130. A foot 132 a, 132 b may engage both ends of the pivot 142. Each such foot 132 may be manipulated by a corresponding block 134 and biasing member 138. In certain such embodiments, the feet may rotate independently on the pivot 142. Accordingly, each foot 132 a, 132 b may engage and release the support surface 66 independently.

A stop 68 comprising a base 130 and foot 132 (or feet 132 a, 132 b, etc.) may configured in any way to improve its operation characteristics. For example, the stop 68 may be formed of a lightweight material (e.g., metal, polymer, etc.). Portions of the material that are structurally unnecessary may be hollowed-out, thinned, or the like to lower the mass thereof. Also, a combination of materials may be used. For example, a foot 132 may include an elastomeric insert 144 providing the interface between the foot 132 and the supporting surface 66. The insert 144 may be replaceable should it wear excessively. Additionally, the stop 68 may include a interchangeable spacer 128 to compensate for wear, or to permit the stop 68 to contact the support surface 66 at a different weighting (e.g., heavier, softer, etc.).

A stop 68 configured to resist rearward roll by engaging the supporting surface 66 may be secured to a cambered, flexible intermediate member 54 as illustrated in FIGS. 6, 7, 16, and 17. Additionally, such a stop 68 may be secured to an intermediate member 54 including a flex region 84, such as those illustrated in FIGS. 9-14. In such embodiments, the flex region 84 may, when properly loaded, permit the stop 68 to contact the supporting surface 66.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

1. An apparatus comprising: a roller ski comprising at least two wheel configured to roll on a surface; a stop connected to the roller ski; and the stop selectively engaging at least one of the surface and the at least two wheels in response to a force of at least a threshold magnitude urging the roller ski toward the surface to resist rearward roll of the roller ski on the surface, the resistance to rearward roll varying with the force.
 2. The apparatus of claim 1, wherein the stop resists rearward roll by engaging the surface.
 3. The apparatus of claim 2, wherein the at least two wheels comprise a first wheel, a second wheel spaced from the first wheel, and an intermediate member connecting the first wheel to the second wheel.
 4. The apparatus of claim 3, wherein the intermediate member is flexible sufficient to travel through a range of motion bounded by an unloaded position and a loaded position, corresponding to the force.
 5. The apparatus of claim 4, wherein the unloaded position is characterized by the stop being spaced a distance from the surface.
 6. The apparatus of claim 5, wherein the loaded position is characterized by the stop contacting the surface.
 7. The apparatus of claim 6, wherein the stop connects to the intermediate member at a location between the first and second wheels.
 8. The apparatus of claim 7, wherein the stop comprises a third wheel.
 9. The apparatus of claim 8, wherein the stop further comprises a unidirectional ratchet interfacing between the third wheel and the intermediate member.
 10. The apparatus of claim 9, wherein the unidirectional ratchet resists rotation of the third wheel in a direction corresponding to rearward roll of the roller ski.
 11. The apparatus of claim 2, wherein the stop resists rearward roll by resisting rotation of a first wheel of the at least one wheels.
 12. The apparatus of claim 11, wherein the intermediate member comprises a first fork corresponding to the first wheel, a second fork corresponding to a second wheel of the at least two wheels, and a deck extending to connect the first fork to the second fork.
 13. The apparatus of claim 12, wherein the first fork is pivotably connected to the deck.
 14. The apparatus of claim 13, wherein the stop comprises an extension extending substantially rigidly from the deck to a location proximate the first wheel.
 15. The apparatus of claim 14, wherein, in response to the force, the first fork pivots with respect to the deck until the first wheel contacts the stop.
 16. The apparatus of claim 15, wherein the intermediate member further comprises a biasing member biasing the first fork with respect to the deck to urge the first wheel out of contact with the stop.
 17. The apparatus of claim 16, wherein the force causes a compression of the biasing member.
 18. An apparatus defining longitudinal, lateral, and transverse directions substantially orthogonal to one another, the apparatus comprising: a first wheel; a second wheel spaced in the longitudinal direction; an intermediate member connecting the first wheel to the second wheel; an stop connected to the intermediate member and selectively and proportionally resisting rotation of at least one of the first and second wheels in response to a transverse load applied through the intermediate member to the first and second wheel.
 19. An apparatus defining longitudinal, lateral, and transverse directions substantially orthogonal to one another, the apparatus comprising: a first wheel positioned to rotate about a first axis extending laterally; a second wheel positioned to rotate about a second axis extending laterally, the second axis being spaced in the longitudinal direction from the first axis; an intermediate member connecting the first wheel to the second wheel; an stop connected to the intermediate member and selectively and proportionally resisting rotation of at least one of the first and second wheels in response to transverse deflection of the intermediate member with respect to the first and second wheels.
 20. The apparatus of claim 19, wherein: the intermediate member comprises a first end and a second end corresponding to the first and second wheels, respectively; and the stop comprises a brake pivotably connected to the intermediate member proximate the first end and a tension member engaging the intermediate member proximate the second end and extending therefrom to engage the brake, the tension member pivoting the brake into contact the first wheel in respect to the transverse deflection of the intermediate member with respect to the first and second wheels. 